1. Field of the Invention
The present invention relates to a light-projecting device provided for indicating a focused point, for example, in a view finder of a single-lens reflex camera.
2. Description of the Related Art
Conventionally, there is known a single-lens reflex camera provided with a function, in which a plurality of distance-measurement points are set for an image to be photographed, and a point, which is in-focus and included in the distance-measurement points, is indicated and superimposed on a subject image in a view finder, as disclosed in Japanese Unexamined Patent Publication No. 2002-268128. Namely, a focusing glass and a superimpose-plate are superposed on each other, and disposed under a hollow pentagonal mirror, and if the number of the distance-measurement points is seven, seven small focusing marks are formed on the superimpose-plate. A light-projecting optical system is provided in a rear portion or an emergent opening of the hollow pentagonal mirror and above an ocular optical system. In a photographing operation, when any point of the distance-measurement points is in-focus, an illumination light beam is radiated from the light-projecting optical system onto the corresponding focusing mark, so that the photographer can recognize the in-focus point.
The light-projecting optical system has a light source and a light-projecting prism, which are disposed at an upper portion of the emergent opening of the hollow pentagonal mirror. Namely, the illumination light beam output from the light source is reflected on the light-projecting prism, and is directly radiated on the superimpose-plate through the emergent opening.
The illumination light beam is reflected on the roof reflecting plane and the third reflecting plane after being reflected on the superimpose-plate, and is apt to enter the ocular optical system, as ghost light. Because of this phenomenon, it sometimes happens that the view finder picture plane is not clear for the photographer, and therefore, it is preferable to remove the ghost light.